Way too much fuel--coming out of the exhaust--22RE

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BigD1

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Just got my 1992 Toyota pickup with the 22RE put back together the other day. Basically rebuilt the top end plus new timing chain and other new parts. Did not have the injectors rebuilt, but I did clean up the holes where the injector seats into the lower intake, and I did install seal kits for each injector.

Went to crank it for the first time, and it fired right up. Started smelling fuel after it ran for about a minute, but could not find a visible leak. Shut it off, and looked for seeping around the fuel connections, but could not find any leaks. Started the engine the second time, and the fuel smell got stronger, and it ran for about another minute before I shut it down. Engine did start to lope right before I shut it down because it was being flooded with fuel.

Fuel was 100% coming out of the exhaust. It was pumping so much fuel it was ridiculous. It has been sitting the last two days waiting on me to fix it. I was so mad at the time because I had put so much love, labor, and money into it. An old gent I know said just walk away from it, and let it sit for a couple days, and then fix it, so that's what I am trying to do now.

Stuck open injector/s, grounded injector/s, fuel pressure regulator stuck closed not allowing fuel to return to tank, and cold start injector malfunctioning by continuously pumping fuel when it's only suppose to pump fuel for seconds on startup is the only things I know that would cause the over fueling.

Going to install a new Kyosan pressure regulator and some new injectors. Want to do some testing before those parts come in. Can't find a noid light that will plug into a Denso fuel injector harness to check and see if I am getting pulses instead of staying on to rule out a grounded injector. None of the noid kits that I have looked at mention Toyota.

Need my truck, so any and all advice would be appreciated. Thanks!
 
Originally Posted By: OVERKILL
Sounds like you are already guessing at the culprit. pinched off return would be my guess.


Especially since it got progressively richer over several minutes.
 
Originally Posted By: OVERKILL
Sounds like you are already guessing at the culprit. pinched off return would be my guess.


The pressure regulator is 25 years old now. It did sit on a work bench dry without fuel for eight days. I am thinking that it just went defective sitting there dry. My understanding of how the pressure regulator functions is that if it gets stuck closed then the return will be shut off, and the fuel will only have one way to go which would be into the fuel rail.

The return hose from the pressure regulator to the return tank line at firewall is about 12 inches or so long, and it is not pinched. Did not mess with the return tank line from the firewall back to the tank. Anything is possible though, and I did not think about it being pinched from firewall to tank, but I do not think it is likely. Thanks for the tip!
 
Originally Posted By: BigD1
Originally Posted By: OVERKILL
Sounds like you are already guessing at the culprit. pinched off return would be my guess.


The pressure regulator is 25 years old now. It did sit on a work bench dry without fuel for eight days. I am thinking that it just went defective sitting there dry. My understanding of how the pressure regulator functions is that if it gets stuck closed then the return will be shut off, and the fuel will only have one way to go which would be into the fuel rail.

The return hose from the pressure regulator to the return tank line at firewall is about 12 inches or so long, and it is not pinched. Did not mess with the return tank line from the firewall back to the tank. Anything is possible though, and I did not think about it being pinched from firewall to tank, but I do not think it is likely. Thanks for the tip!



Does the regulator have a vacuum port on it? I know from my experience with return-based Ford vehicles that the regulator was vacuum controlled (vacuum reduced fuel pressure at low load) and that if the diaphragm in the regulator ruptured that they fuel would be drawn straight into the intake via that vacuum hose and would result in a scenario strikingly similar to what you are presently experiencing.
 
Originally Posted By: OVERKILL
Does the regulator have a vacuum port on it? I know from my experience with return-based Ford vehicles that the regulator was vacuum controlled (vacuum reduced fuel pressure at low load) and that if the diaphragm in the regulator ruptured that they fuel would be drawn straight into the intake via that vacuum hose and would result in a scenario strikingly similar to what you are presently experiencing.


Yes the fuel pressure regulator has a return line and a vacuum line.

Very good diagnosis because I think that's what is going on. Fuel being sucked straight into the intake via vacuum hose because of a bad regulator. Will be easy to check. Will pull the vacuum hose off the regulator port, and see if it leaks fuel.
 
Originally Posted By: bubbatime
Don't forget to change the oil when you get it sorted out. That much fuel in the oil is not good for lubrication.


I will. I pulled the dipstick yesterday, and it already had a faint smell of fuel.
 
Originally Posted By: The_Eric
You smell fuel- raw fuel or unburnt/poorly burnt/rich out the tailpipe?


It's was raw fuel coming out of the tail pipe. It was blackish looking from the soot in the exhaust system. It was also coming out of the exhaust manifold too where it connects to the down pipe. Thought it was going to catch on fire. Engine only ran for a couple minutes total, and it did run good up until it started loping because of the cylinders being flooded.
 
Originally Posted By: Chris142
Cold start injector is a common failure.


I will unplug it after it starts running to see if the flooding stops. Not sure of the best way to test it.
 
Originally Posted By: BigD1

I will unplug it after it starts running to see if the flooding stops. Not sure of the best way to test it.


That won't help - because if it's stuck open, it's going to flow whether there's an electric signal or not!
 
Originally Posted By: Linctex
Originally Posted By: BigD1

I will unplug it after it starts running to see if the flooding stops. Not sure of the best way to test it.


That won't help - because if it's stuck open, it's going to flow whether there's an electric signal or not!


Yes that sounds right.

I did find how to test the resistance of the cold start injector. Otherwise, the only other way that I have found to test it is to crank the engine with the cold start injector pointed down into a container to catch fuel, and watch what happens. Seems dangerous to do it that way.
 
Clamp off the fuel line to the cold start injector. Most engines start fine without it. Also is the gunk coming out of the tail pipe just condensation from sitting?
 
Last edited:
Originally Posted By: andyd
Clamp off the fuel line to the cold start injector. Most engines start fine without it. Also is the gunk coming out of the tail pipe just condensation from sitting?


Can't clamp the line because it is a hard line from cold start injector to fuel rail. I could disconnect the hard line from the fuel rail, and then use a regular bolt, and a crush washer to block it off. Then just unplug the cold start injector, and leave it installed in the plenum.

Thanks for bringing that up because I did not think about doing it until you got me thinking about it!

No question about it. It was 100% fuel. Going to trouble shoot it later today, and the first thing I am going to check is the fuel pressure regulator. Pull the vacuum hose off the regulator, and crank it over, and hope I see fuel pumping out the vacuum port.
 
Happy day! I finally figured out what I did wrong.

Had the EGR vacuum modulator bottom/big hose hooked to the fuel pressure regulator return line.
06.gif


Fuel pressure regulator return line was hid up under the charcoal canister, and I did not see it when I put it back together.
 
Wow, glad that got fixed. Is the oil change interval compromised by the increase fuel issue? Not enough time to mix with the sump?
confused.gif
 
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